Just to bring this thread to a close, I've fought my Scottish heritage tendencies for a short period and have booked in Tesla to replace the trim. 

I also visited a couple of panel/paint shops - one would have filled the crevices and painted a small part of the trim for $120 which, while cheap as, in the end didn't fill us with the confidence that the scratches wouldn't remain fairly obvious.

Another provided an estimated cost to remove the trim, fill, repaint and replace at over $500+GST, which I reckon is a complete have. I'm guessing this kind of charge is based on assumptions as to what OEM parts replacement would cost and, if he comes in a bit under, he'd get the work. In this case he was wide of the mark - Tesla's charging $440, which seems pretty reasonable.